Cover his ass

: Can someone please tell me, what does "cover his ass" mean? I found the source of "cover your ass" in this site, but still have no idea of what that means. Thanks a lot.

I'll take the chance of making an a s s of myself here, but I think the meaning (which is clear) and the origin are a bit mixed up. When someone does something to "cover his ass" he is trying to protect himself in advance from possible criticism (often correctly assigned in this case) or prosecution by concealing or disguising his involvement in something that could go wrong (by failing or by being made public), or by making sure the responsibility will fall upon someone else, or by giving himself a very plausible reason or excuse for his actions. My guess is that the lineage of the phrase comes from "covering one's rear" in the military sense (protecting oneself from attack from behind), which, because of the equivalence in colloquial language between rear and ass, becomes "covering one's rear end." The phase has an unpleasant connotation: either you need to protect yourself from the consequences of your sneaky action, or your action, however justified, will open you to attack by sneaky people.

Another putative descendant of "Covering the rear" in the military sense (like Roland at Roncesvalles), is the phrase, "I'll cover your back" (I'll protect you from attacks from behind), which becomes "I've got your back." This has no shady connotation whatever. SS